The Best Interior & Exterior Finishes for Your ADU

Three Common ADU Finishing Levels

• Standard Finishes: ADUs on a strict budget. Most common for ADUs intended to be rentals or return on investment-focused investors.
• Standard Plus Finishes: ADUs with some budget for a few upgrades. Usually, we see Standard Plus finishes in ADUs with more flexible use cases, such as guest houses, age-in-place options, family and friends, and the potential for rental income.
• Premium Finishes: Designer ADUs for family, retirement, or guest spaces, often matching the existing home. These are high end ADUs for high end homes or situations.

Standard: The No-Frills, Economical ADU

Exterior Finishes

• Roofing Material: We typically recommend 30-40 year composition shingle roofs, which is standard for residential construction.
  • Alternatively, a torch down or built-up-roof solution is standard for roofs with a pitch lower than 2/12 or a flat roof. This is also common in Los Angeles for Spanish-style homes with flat roofs.
• Exterior Wall Finish: Stucco tends to be the best balance of cost and longevity, as cheaper options such as vinyl siding may save you up front but have a shorter lifespan. This isn’t a great outcome if you are hoping to earn top rental income for the long term.
• Entry Doors: Building code requires that an ADU have at least one single swing door for entry and exit. If sliding glass doors are your preferred choice, it is important to note that an additional swing door will be required.

Interior Finishes

• Lighting: The most cost effective choice for lighting is a surface mount fixture, which provides versatility in light coverage and fixture style.
• Flooring: When pets or active kids are part of the equation, luxury vinyl plank (LVP) is a great flooring solution. Gone are the days of rolling out cheap vinyl sheet flooring - over the last 10 years, vinyl flooring has greatly improved as a product. LVP is now installed in pieces, just like a true hardwood floor, and each plank is offered in a range of wood grain and stain patterns with faux wood texture. This scratch-proof, waterproof, and highly durable flooring is a great starting point for most ADU projects.
• Doors & Windows: Vinyl windows are the industry standard and come in a wide variety of sizes and operational mechanisms (sliding, awning, double hung, fixed, etc.). They are easy to install and easy to replace if future repairs need to be made.
• Bathroom: Tile bathrooms are standard with Cottage. Pricing can range from $3-4/square foot and up to $10 or even $20/square foot for tile. The difference in quality is minimal, but a wider variety of material (ceramic, stone, porcelain), texture/finish, or tile sizing is available with higher cost selections.
  • An alternative to tile is to continue the luxury vinyl plank flooring into the bathroom. LVP is durable and waterproof, and the single flooring material selection through the ADU can reduce labor and material costs for the project.

• Kitchen: So many choices! Cabinet style, drawer and door pull hardware, countertop material, backsplash style and material, and faucet fixtures offer many places to choose from. Cottage provides guidance in the form of pre-selected kitchen design packages, which can help keep your decisions to a minimum.
  • The most affordable sink option is an over the counter stainless steel sink—easy installation and simple for future repairs or modifications.
  • All Cottage kitchen sinks come standard with a disposal.

• Appliances: Appliance packages for an ADU can range widely. A small ADU with basic appliances from a brand like Whirlpool can cost as little as a few thousand dollars.
  • When ROI or overall budget is the focus of an ADU build, a base appliance package will serve your needs quite well.
  • Cottage typically recommends brands like Whirlpool or Frigidaire, both of which are reliable brands that come in a variety of appearances.

Standard Plus: Flexible ADU Use Cases - Family, Friends, Maybe More

Exterior Finishes

• Roofing Material: If preferred, a more substantial 50 year presidential shingle is an option, but a 30-40 year shingle is still a great choice and the most popular option.
• Wall Finish: A textured and colored stucco is a good option for an ADU’s exterior finish. Alternatively, Hardie Board siding (which can be installed as horizontal planks or in a board and batten style) offers incredible durability and mimics a traditional wood siding look. The cement fiberboard composition of Hardie Boards offers a high level of fire resistance as well.
  • Board and batten, composed of wood or Hardie Board sheeting and detailed with 2” boards running vertically on the surface, is a popular choice for a modern farmhouse aesthetic. It’s also more cost effective than redwood or cedar horizontal siding.
• Entry Doors: French doors are the most common upgrade for exterior doors. They satisfy the swing door code requirement and can provide more light and an open feeling to the ADU. Common French doors are full light panels (glass with a 6-8” wood trim) or mullioned doors (glass panels with cross sectional wood accents to create a grid).

Interior Finishes

• Lighting: A mix of recessed lighting in the living room and kitchen areas with surface mounted fixtures in the bedroom and bathroom are recommended as a cost-effective lighting solution for these ADUs.
• Flooring: Engineered hardwood flooring is the most common flooring option for Cottage ADUs. Composed of multiple layers of plywood and topped by a layer of finish wood (commonly oak or maple), engineered hardwood floors are a cost-effective way to achieve a real hardwood look and feel. Surprisingly, engineered hardwood is less expensive and more durable than hardwood.
• Doors & Windows: Fiberglass windows offer a level up in quality, which comes with an increase in cost but greater flexibility when it comes to color selection and the ability to customize paint color.
• Bathroom: No need to spend exorbitant amounts of money on tiling your bathroom. There are plenty of quality tile solutions within the $5-6/square foot range. Consider managing costs with a ceramic shower pan with tile walls in the bathroom, rather than a full tile shower.
• Kitchen: The most common sink in our ADUs is an under-mounted stainless steel sink. Sitting flush under the countertop, it makes for easy cleaning and smooth lines around your sink area.
• Appliances: LG, GE and Samsung are great options for kitchen appliances. By going with one brand for your appliance package, you are not only able to save money but keep future maintenance needs simple with a one stop shop for repair services.

Premium: Luxury ADUs to Match The Main Home

Exterior Finishes

• Roof Material: The 50 year presidential shingle is the most durable and substantial composition shingle roof option.
  • Metal roofs, often referred to as “standing seam roofs”, have also gained popularity. The cost of such a roof can range anywhere from $8-15,000 more than a traditional shingled roof
• Wall Finish: Cedar shingle, horizontal redwood siding, and smooth stucco are the most common premium exterior finishes for our ADUs. A combination of smooth stucco and cedar siding can give your ADU a beautiful modern look.
• Entry Doors: Large sliding or accordion glass doors are a go-to option to make a statement for your ADU entry. They provide that famous Californian indoor-outdoor living when connected to a backyard or deck space and allow for tremendous light into a space. If the only entrance to the ADU is the large glass panel wall, then one of the panels must function as a swing door by code.

Interior Finishes

• Lighting: Recessed lighting can provide sleek lighting throughout a space—typically selected in living rooms and kitchens. The cost difference between recessed and ceiling mounted lighting can be substantial, as a single recessed light can costs $2-300 more and light a much smaller area than a single comparable surface mounted light.
• Flooring: Engineered hardwood flooring is being installed in high end, multi-million dollar homes and is an excellent premium flooring choice. That said, tried and true hardwood flooring is a common option for our premium ADUs. These floors will stand the test of time, with the ability to sand and refinish for decades to come.
• Doors & Windows: Fiberglass windows, can be made in a more modern style akin to high-end aluminum or bronzed aluminum styles. Because Title 24 energy regulations in California make metal-framed windows difficult to permit, fiberglass is the upgrade of choice for our premium ADUs.
• Bathroom: Stone and porcelain tiles come in a wide variety of looks and textures. Porcelain is more durable than a traditional ceramic tile and stone (whether it’s a slate or marble) is not only the most durable option but can make the biggest statement when it comes to the color and texture of your ADU bathroom.
  • Large bathrooms can accommodate a dual basin vanity (“Jack and Jill”) and are a great option in high end bathrooms where space is not a constraint.
• Kitchen: Farmhouse ceramic sinks have become popular—examples of which can be seen all over Pinterest, Instagram, and in Dwell magazine. They offer a unique look and a large, open basin for washing. In many of our premium ADUs, an undermount stainless steel sink is still the go-to option.
• Appliances: Thermador and Sub-Zero fridges are the crème de la crème of the cold food storage world. When it comes to cooking, Viking and Wolf ranges are the preferred choice of professional chefs and foodies who want to cook on the highest level equipment. For a full size kitchen, going with top of the line appliances can cost upwards of $12,000 more than other basic options.

What are the Right ADU Finishes for My Needs?